1. Field of the Invention
The present invention relates to a power-on device, and particularly to a power-on device that switches power supplies dynamically according to voltages of batteries to prevent charge capacities of batteries from falling too low to start immediately, circuit systems such as handsets supplied by batteries.
2. Description of the Related Art
Generally, most handsets, laptops and other portable electronics are primarily supplied by batteries, which meet requirements of portability. Batteries have a tendency to self-discharge. When handsets are turned off or batteries are removed from handsets, batteries return to the lowest form of energy. The amount of self-discharge differs with each system and cell design. NiCd and NiMH battery chemistries exhibit an inherently high self-discharge. Poor manufacturing practices and improper use can accelerate this phenomenon. Owing to limits of volume, batteries can have limited charge capacities. Unused after a long time, batteries have too low a charge to start handsets and display handset states, such as charge capacities, proving to be quite inconvenient.